Although optical networks are being deployed in military and commercial applications with increasing regularity, electrical signal networks are still in wide use, as they can provide low-cost, more robust solutions depending on the application. Plus, although optical networks theoretically offer higher bandwidth, electrical networks are capable of operating over large enough bandwidth regions to satisfy many applications.
As with optical networks, it is desirable in electrical networks to maintain signal integrity throughout the network, which means reducing signal losses at each node, at each device, and on the electrical lines coupled between nodes and devices. To ensure network integrity, designers and maintenance personnel use network analyzing equipment to identify faults in an electrical network. Typically, such analysis requires that technicians physically examine different portions of the network with analyzing equipment until the fault is identified—a time consuming process. To expedite analysis, there is a need for built in testing within network devices, e.g., transceivers, so that devices themselves are able to monitor their operating conditions and/or the operating conditions of other devices on the network. This network self-diagnosis would greatly reduce the time spent by technicians in trying to isolate faults.
Despite the need for built in testing capability, in many applications including aerospace applications, space constraints and costs limit a designer's ability to make devices with proper testing capability. It is therefore desirable to have techniques for obtaining diagnostic information using existing network components and without substantially interfering with the existing network devices or appreciably increasing network size, cost, or complexity.